Vitamin K, a vitamin that promotes normal blood clotting, also helps you maintain bone density as you age. Elderly women who lack vitamin K in their diet may have a higher risk of fractures related to osteoporosis, a degenerative bone disease. By eating more dark, leafy green vegetables and taking vitamin K supplements under your doctor's supervision, you may be able to maintain healthy bone density and prevent osteoporosis. If you take blood-thinning medication, consult your doctor before increasing your vitamin K intake through food or supplements.
Bone Mineralization
After menopause, a decline in your body's production of reproductive hormones increases your risk of developing frail, porous bones. When your bones begin to lose their mineral content more rapidly than new bone can form, you may develop osteoporosis, a bone disease that makes your skeleton frail and increases your risk of fractures. Osteocalcin and other proteins in bone rely on vitamin K to bind calcium to the bone matrix. (See References 4, "Bone Mineralization") Without adequate vitamin K from food or supplements, your bones may lose density, according to the Linus Pauling Institute at Oregon State University. Elderly women who eat few green vegetables or who take blood-thinning medications that counteract the effects of vitamin K may have an increased risk of a vitamin K deficiency.
Osteoporosis Prevention
In a 10-year Nurses' Health Study of women ages 38 through 74, Diane Feskanich and co-authors found that women who consumed lettuce, broccoli, spinach and other foods high in vitamin K every day had a lower rate of hip fractures than women who ate these foods only once or twice a week. This study, published in the January 1999 issue of the American Journal of Clinical Nutrition, indicates that postmenopausal women may reduce their risk of osteoporosis-related fractures by eating foods rich in vitamin K.
Recommended Dosage
To prevent osteoporosis, the Linus Pauling Institute recommends that older adults older than 65 should take a multivitamin supplement containing 10mcg to 25mcg vitamin K, along with a minimum of 1 cup leafy dark green vegetables, such as kale or spinach, every day. By replacing the saturated fats or trans fats in butter and margarine with olive, canola or soybean oil, you can also increase your intake of dietary vitamin K. One cup raw spinach offers 145mcg of vitamin K; 1 cup chopped broccoli has 220mcg; and 1 tbsp. olive oil has 8.1mcg vitamin K, according to the Linus Pauling Institute.
Precautions
If you're taking warfarin or another blood thinner due to a heart condition or a risk of developing blood clots, supplemental vitamin K may interfere with your medication. Older women taking blood thinners can generally consume up to the adequate intake of 90mcg vitamin K each day without medication interactions. By maintaining a consistent, moderate dietary intake of foods that contain vitamin K and following your doctor's recommendations, your blood clotting time may remain stable, the Linus Pauling Institute says. Work closely with your doctor to develop a plan to maintain your vitamin K intake without inhibiting the effects of blood thinners.
References
- American Journal of Clinical Nutrition: Vitamin K Intake and Hip Fractures in Women: A Prospective Study; Diane Feskanich, et al; January 1999
- Linus Pauling Institute at Oregon State University: Micronutrient Requirements for Older Adults: Vitamin K; December 26, 2010
- MedlinePlus Supplements: Vitamin K; November 19, 2010
- Linus Pauling Institute at Oregon State University: Vitamin K; May 2008
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